1. Field of the Invention
The present invention generally relates to an automated tester for charging the air brake pipe of a train consist to a predetermined pressure and checking pressure at a central location and, more particularly, to an Initial Terminal Tester (ITT) comprising a Head-Of-Train (HOT) unit which controls the charging and venting of air pressure at the front end of a train, an End-Of-Train (EOT) device which monitors and transmits air pressure data, and a Central Control Console (CCC) which monitors both the HOT and EOT devices on each track of a train yard.
2. Description of the Prior Art
Before a train may leave a terminal, it must pass an initial terminal air brake test. The charging and testing is often done in the train yard using a yard air supply, several pressure gauges, and a watch.
A train is made up of many individual cars, termed a consist, that are placed on the same track by a yard crew for eventual coupling to one or more locomotives. As soon as the consist is completed, the yardmaster turns the track over to the car department for hookup and testing. The car department dispatches a car inspector to that track with the following duties: (1) inspect all cars in the consist for defects, and (2) hookup and test, using a yard air plant, the air brake system.
The car inspector generally goes to the head of the track, i.e., that end which will be nearest to the hauling locomotive, hooks up the yard air to the first car, inspects the first car and then couples the air hoses between the first and second cars, turns the air "in" and repeats the procedure for each car in the consist. That is, he next couples the air hoses between the second and third cars, goes back to the coupling between the first and second cars and turns the air "in". Then, he couples the air hoses between the third and fourth cars, goes back to the coupling between the second and third cars and turns the air "in", and so forth. This is known as "carrying the air with him". By utilyzing this procedure, when the car inspector finishes inspecting and hooking up the air, the air pipe of the consist is generally fairly well charged. Charging must continue, however, until a pressure of 65 psi is attained at the opposite end of the consist, and so the inspector waits at the end of the train until that pressure is attained. A 15 psi service reduction is then made. After waiting 60 seconds for the brake pipe pressure to settle, the leakage is observed for another 60 seconds. If the leakage exceeds 5 psi in that period, the consist fails the test. If the pressure has not reduced to 57 psi, it is reduced to that amount.
In order to make a brake test, the car inspector then needs to walk back to the front end of the consist, turn off the yard air, make a 20 psi reduction in the air pipe, and "walk the brakes". The 20 psi reduction in air pressure should cause the brakes of all cars in the consist to be applied. By "walking the brakes", what is meant is that the car inspector walks the length of the consist checking the brakes on each car to see that they have been applied. Once he has verified that all the brakes have been applied, he must then walk to the front of the consist, reapply yard air, build the pressure back up and "walk the release", i.e., check brakes on each car to see that they have released. Alternatively, the inspector may make a "roll-by release inspection" depending on current Federal regulations and company rules.
This procedure requires the car inspector to make five trips between the head and rear of the train consist to completely inspect the consist or, where a "roll-by release inspection" is made, four trips between the head and rear of the consist must be made. Where there are sufficient personnel, two car inspectors will work together, one coupling hoses and the other turning the air "in" and so on, but the foregoing procedure is still followed.
As an additional responsibility, the car inspector has been given the duty of applying the End-Of-Train devices to the trailing coupler of the last car of the consist. End-Of-Train or EOT devices are designed to be mounted on the trailing coupler of the last car of a train and are connected to the brake air pipe for monitoring, among other things, the brake pipe pressure. On a more or less periodic basis, data pertaining to the air pressure in the brake pipe is transmitted to a receiver in the locomotive where it is decoded and displayed for the engineer.
Because of the considerable labor involved, it is desirable to automate the initial terminal air brake test. There are a number of prior patents which relate in one way or another to air brake testing, but none suggests a procedure or apparatus for automating the initial terminal air brake test. For example, U.S. Pat. No. 2,637,201 to Meier discloses an apparatus for testing train brakes prior to coupling to a locomotive in which one man operates the testing device to apply the brakes through the train, then walks to the other end of the train to check the brake application. He then takes steps to cause the testing device to release the brakes and walks back along the train to check the brake release on individual cars.
U.S. Pat. No. 2,993,199 to Browne et al. describes automatic inspection apparatus for checking brake mechanisms either from a locomotive or a control at a yard charging station which uses electric pulse producing means responsive to the functioning of the brake mechanisms, and means located on the locomotive or at the yard charging station. The various units, i.e., those on the locomotive or at the yard station or the cars and caboose, are interconnected in a circuit.
U.S. Pat. No. 3,784,813 to Ryan shows an apparatus for testing the complete integrity of a train brake system which utilizes a pressure switch in the brake line of the last car that allows coupling between a transmitting and a receiving coil on opposite sides of the car to indicate operation of the system.
U.S. Pat. No. 4,041,470 to Slane et al. shows a monitoring and reporting system to monitor brake, door, motor and other functions at each car. Sensor, display and processor units are included in each car, and means are provided in the lead car to interrogate other cars which respond with fault information. A data link interconnects the cars.
U.S. Pat. No. 4,056,286 to Burkett discloses a remote control brake system for a train which comprises transceivers at the locomotive and caboose, and includes means for initializing when charging begins to assure that brake pipe pressure at the caboose corresponds to locomotive brake pipe pressure.
U.S. Pat. No. 4,066,299 to Clements discloses apparatus for locating a malfunctioning brake control valve on a train in which the brake pipe at the head end and rear end of a train are equipped with pressure activated devices which can transmit a radio frequency (RF) signal to a receiver located with an engineer or at the rear end. Determining elapsed time after a transmission enables location of a faulty brake control valve.
U.S. Pat. No. 4,361,825 to Shockley shows an automatic train air brake monitoring system which continuously provides signals of elapsed time when air brakes are applied or released, as well as an indication of the quantity of the braking effort.
U.S. Pat. No. 4,487,060 to Pomeroy discloses a brake monitoring system which includes End-Of-Train transmitting equipment.